An Insight into the Hepatoprotective Activity and Structure-activity Relationships of Flavonoids

Background: Flavonoids are a class of polyphenolic bioactive compounds obtained from plants, which have a wide range of chemical structures and properties. More than 9000 distinct flavonoid molecules have been identified, and have been found to regulate numerous developmental processes and play key biological roles in living organism. Objective: This review aims to highlight the hepatoprotective potentiality of flavonoids and co-relate their pharmacological activity with their chemical structure. Methods: With advancement in the field of research related to phytochemicals, it is evident that flavonoids have versatile health benefits, viz., antioxidant property, free radical scavenging capacity, anticancer activity. The basic structures are C6—C3—C6 rings with various substitution patterns, resulting in a succession of subclass compounds, and the relationships between chemical structures and bioactivity have previously been investigated. Results: The hepatoprotective effects of bioactive flavonoids derived from plants have been widely linked to their antioxidant activity, antiinflammatory activity, effects on sterol regulatory element-binding proteins (SREBP), peroxisome proliferator-activated receptor gamma (PPARγ) receptors, and inflammatory mediator cytokines according to numerous studies. The C2-C3 double bond at the A ring, as well as the hydroxyl groups of C3′or C4′, and the carbonyl group at position C4,have been shown to augment their hepatoprotective activities; however, hydroxymethylation at C3′ and C4′ has been found to diminish the hepatoprotective activity. Conclusion: The impact of flavonoid moieties and the structure-activity relationship of flavonoids related to combating various hepatic disorders have been vividly discussed in this review paper.